The present invention is in the field of high frequency medical X-ray generators. More particularly, the invention is directed to improvements in high frequency X-ray generators for radiographic or medical imaging applications, or so-called diagnostic X-ray equipment. More particularly yet, the present invention concerns a novel and improved high voltage transformer assembly for a high frequency medical X-ray generator.
Generally speaking, high voltage transformer circuits for medical X-ray generators utilize a plurality of relatively large circuit components which have relatively high power-handling capacities. For example, relatively large high voltage transformers are utilized for both anode and cathode portions of the transformer circuit, and relatively large filter capacitors are also required for use with these high voltage transformers. In fact, the power handling requirements are such that the capacitance elements in both the anode and cathode circuits are generally not supplied with the transformer. Therefore, the output voltage of such a transformer is in the form of an unfiltered rectified AC. However, in our novel arrangement, the necessary capacitance elements are included, being formed by coupling in circuit a plurality of relatively large capacitor elements of relatively high power handling capabilities.
Similarly, the respective rectifier portions of the anode and cathode transformer circuit portions are generally formed in our novel arrangement by coupling in circuit a large number of smaller individual rectifier or diode elements, again to achieve the necessary power handling capacity of the circuit.
Additionally, positive and negative kilovoltage (KV) outputs from the high voltage transformer circuit are taken at a relatively high impedance output, which is established by bridging the positive and negative ends of the high voltage transformer circuit with high impedance resistance elements. Preferably, the required high impedance and high power handling capabilities of these resistance elements are achieved in our novel arrangement by using a plurality of relatively smaller resistor elements coupled in circuit to form the necessary high impedance circuit element.
Finally, a filament transformer for the X-ray tube filaments may also be provided, in accordance with our present invention, as part of the high voltage transformer assembly.
Our invention advantageously provides a relatively orderly and easy to assemble "packaging" arrangement for the high voltage transformer circuit. Our method of assembling and packaging the foregoing circuit elements advantageously provides a unitary or modular type component for relative ease of assembly in manufacturing. Moreover, our novel modular form of assembly permits relative uniformity in wiring, circuit connections and the like from one transformer circuit and assembly to the next. This permits a high degree of reliability in manufacture, as well as a relatively high degree of uniformity from one production unit to the next, and substantially minimizes variations in performance among assemblies produced in accordance with our invention.
This high degree of uniformity and repeatability of results utilizing assemblies made in accordance with our invention will be appreciated to promote uniform and repeatable results in the field when these assemblies are further assembled with medical X-ray units. Hence, with such a high degree of repeatability and uniformity, damaged units in the field can readily and simply be replaced by new or refurbished assemblies, with confidence that the performance of the replacement assembly will be virtually identical to that of the original high voltage transformer circuit upon initial installation.
Hence, our invention, by providing a relatively orderly and uniform assembly, promotes not only a savings in manufacturing cost, but also both increased reliability and savings in costs of providing field service.
We have also found in connection with our high voltage transformer assembly that encapsulate-type filament transformers may advantageously be used as the filament transformer for the X-ray tube. Moreover, such encapsulate transformers may readily be mounted to the high voltage transformer assembly, thus further simplifying the overall assembly of the medical X-ray equipment.